Fewer than one percent of wastewater injection wells across the United States have been potentially linked to induced seismicity, according to a new report by Energy In Depth. The report, entitled “Injection Wells and Earthquakes: Quantifying the Risk,” consults data from the U.S. Geological Survey (USGS) and several peer-reviewed studies to examine the number of injection wells that have been suspected as causing earthquakes, compared against the total number of operating injection wells. The report includes breakout statistics for several states as well, including Oklahoma, Texas, Colorado, New Mexico, Ohio, Kansas, and Arkansas.
Below are the key findings, by the numbers:
- Total number of U.S. disposal wells – 40,000 (approx.)
- Number of U.S. disposal wells potentially linked to seismicity – 218
- Percentage of U.S. disposal wells potentially linked to seismicity – 0.55%
- Percentage of disposal wells operating without seismicity – 99.45%
- Total number of Class II injection wells in the United States – 150,000 (approx.)
- Percentage of Class II injection wells potentially linked to seismicity – 0.15%
- Percentage of Class II injection wells operating without seismicity – 99.85%
The report helps to quantify the risk of induced seismicity from underground wastewater disposal, demonstrating that despite prevalent media coverage of each seismic event, the number of wells even potentially linked to earthquakes is comparatively small across the United States. Even in the individual states where most of the attention on induced seismicity has been focused, the vast majority of injection wells are operating aseismically.
In recent years, scientists, regulators, and industry have come together to implement a number of measures to mitigate the risk of induced seismicity, including resource and data sharing to empower states to adopt best practices. Many states have also updated their rules and guidelines for injection well permitting, and companies have spent tens of millions of dollars in mitigation procedures – many of which were voluntary – in order to further reduce risks.
To access the full report, and the state specific fact sheets, click the links below.